Does anyone know the procedure for setting the throttle body valve position on a ’95 318i auto? Yes, I know the idle is set automatically but this car was missing the adjustment screw for the throttle body valve when I got it.

Some background . . .

I bought this car for my 16 year old son back in December. For the most part the car ran fine but always ran like crap for about 20 seconds after starting it. It would occasionally blow blue exhaust smoke so my assumption was that the valve guide seals were gone and oil was causing the poor startup. But more often than not, there would be absolutely no signs of oil burning but the crappy idle was still there.

This progressively got worse to the point that the car would not idle until it had been run for a few minutes. My son got pretty good at keeping it running and he never told me it had gotten so bad. I drove it last weekend to check it prior to taking it in for inspection – obviously it was not going to pass so it was time to go to work. After reading “Mr.M’s” excellent writeup on cleaning the idle control valve (http://forums.bimmerforums.com/forum...d.php?t=454501) I began to suspect that part.

It had thrown codes for a faulty cylinder 3/4 knock sensor a few times so I had pulled one from a salvage yard . . . yeah, I know, pretty stupid for a part that is so danged hard to get to. I decided to tackle this while working the ICV. Also, the O2 sensor had thrown codes so I got a new one of those also. Oh, and one other thing – the heater valve was leaking coolant, so – you guessed it – I had a few of them from my favorite salvage yard ready to install.

So, armed with a free Sunday afternoon, I dove in. Getting to the ICV and cleaning it was very easy (especially after reading the DIY) but changing the knock sensor was a massive pain in the butt! Anyway, I did manage to get that done, too. Next, I replaced the heater valve, and while I had it out, I cleaned the crankcase vent valve. Honestly I have no idea how to check it, but sucking (no jokes, please) on the vent on top of it seemed to indicate that the diaphragm in it was ok. I cleaned the internals with carb cleaner just as a precaution.

While I was this deep with greasy cuts oozing blood, I decided to check the DISA valve. All the vacuum hoses on it were basically rotted to nothing, and the DISA valve itself was bad. I’ve got plenty of spare vacuum hose, but the DISA valve was another issue. A quick check of realoem.com shows that it costs somewhere around $50 but recent posts said it’s more like $70 to $80 at the dealer. I’ve yet to find it at Pelican.

Bein’s as I’m the King of all Cheapskates, I decided to try to rebuild the DISA valve. I managed to separate the two parts of the vacuum solenoid. The rubber diaphragm was shot as I expected. I managed to find some nice rubber-coated nylon cloth to use as a replacement that I “harvested” from a donor sports bag. I used quick-set epoxy to put it all back together . . . it is almost perfect but it does have a slight, slight vacuum leak. Oh, well, I enjoyed the artistic effort.

I put it back on the car and after getting everything back together the car fired right up and ran like it had gotten a new lease on life! That’s the sweetest sound, especially after fighting with it for many hours.

However, the idle was still not quite perfect. It would smooth out but seemed to hunt for the correct speed for the first few seconds after starting. As I mentioned at the top, the throttle valve position set screw was missing so I decided to replace it and see what would happen. After several tries, I’ve found a setting that seems to work fine – the idle quickly settles after starting. But if there’s an official BMW procedure for setting it I’d like to know what it is.

I cleared the codes and did about a 20 mile test drive. Got another CEL but this time it was for the O2 sensor so I replaced that, too. Another test drive and no CEL.

Life is good.